1. Field of the Invention
This invention relates to a unit removably mountable to the body of an image formation apparatus such as an electrophotographic copying apparatus or an information recording apparatus. It also relates to an image formation apparatus provided with such unit.
2. Description of the Prior Art
Description will hereinafter be made, for example, of an electrophotographic copying apparatus.
In the electrophotographic copying apparatus of the prior art, interchange or supply of expendables is carried out in the following manner. For example, interchange of the photosensitive drum as an image bearing member, which is rotatably supported on a shaft fixed to the apparatus body, is accomplished by removing a shaft fixing member fixed to a side plate of the apparatus body, and then withdrawing the drum from the shaft. Supply of toner to the developing device hopper containing toner therein is accomplished by knowing the toner supply time from detecting means (such as, for example, a device for detecting the amount of remaining toner) provided in the developing device or hopper, and then supplying toner to the hopper.
Since the hopper is fixedly provided in the body of the apparatus, not only is it difficult to supply toner to the hopper but also scattered toner may ingress into the apparatus body to contaminate the interior thereof. Further, waste toner collected from the photosensitive medium by a cleaner is stored in the interior of the apparatus body and must be thrown away when suitable detector means detects that the waste toner container is almost full of waste toner.
When the waste toner is thrown away, the container must be moved while keeping its horizontal position and therefore, the toner can be split or scattered thereby contaminating the interior and exterior of the apparatus or contaminating the clothes of the operator.
As described above, with the prior art apparatus, interchange or supply of expendables is cumbersome and there is the undesirable possibility of contaminating the interior and exterior of the apparatus or contaminating the clothes of the operator. Moreover, since supply and discarding of the drum and toner are carried out individually service is, the number of times required is increased.
Furthermore, the number of portions for mounting respective expendables to the apparatus body has increased and this has led to complexity of the apparatus.
For these reasons, a technique disclosed in U.S. Pat. No. 3,985,436 has been proposed. However, with this technique, even if toner remains in the toner supply device, the unit must sometimes be interchanged when other expendables reach the end of their life. This may lead to waste of developer.